The worldwide telephone system presently existing, which has taken over 100 years to develop and build, is based upon single-line and multiple-line standards adopted by all countries. The multiple-line telephone systems are under a standard called "1A2". This standard has been complied with by most commercial, institutional and governmental users where multiple-line telephnes were required.
The 1A2 standard was originally developed utilizing electromechanical (i.e., analog) technology. This is still the predominant technology used in existing installations. However, in recent years many telephone systems have been installed using the newer electronic (i.e., digital) technology. The key difference between the 1A2 systems and the electronic systems is that the 1A2 system uses electromechanical components and large diameter 25-wire pair cables (50-wires), while the electronic system uses digital circuitry and a slender cord with only one to four wire pairs. Moreover, electronic systems and the electronic telephones used with the systems provide a much broader range of desired features than does the typical electromechanical system. Consequently, sales of electronic business telephone systems have been growing at a rapid rate in recent years. Unfortunately, electronic systems are new and relatively unproven, while the 1A2 electromechanical system has been in use for more than 25 years and has proven to be a reliable and dependable business telephone system.
Electronic telephone systems are being sold to new installations and also to upgrade existing electromechanical systems. Unfortunately, where an electromechanical system is already installed, the cost of conversion from the electromechanical system to an electronic system is very high since the entire system must be replaced. The replaced equipment includes the electromechanical key service unit, the individual telephones and the cabling which extends between the key system unit and the telephones. Replacement, particularly of the key service unit, is required because electronic telephones work only with key service units which are specifically designed for electronic telephones. Replacement of the cabling is required because electronic systems utilize slender and flexible approximately 8-wire cords rather than the heavy 50-wire cables and large 50-pin connectors necessary for electromechanical systems.
It will therefore be appreciated that there is a need for a low cost and easy to install telephone conversion device which allows the user to continue using the existing electromechanical key service unit and 50-wire cabling, while allowing the use of full-feature electronic telephones. The conversion device should allow the interface of any single-line electronic telephone with any 1A2 electromechanical key service unit, including ones designed for rotary dial and push button systems.
Installation of the conversion device should not require the services of a telephone system technician and should be accomplished simply by plugging the device into the 50-pin connector located at the wall or floor outlet of the telephone user's stations, without any modification of the key service unit or the existing cabling or connectors. The conversion device should use a conventional slender and flexible conventional six to eight wire cord running between the outlet and the electronic telephone being used with the conversion device, thus doing away with the need for a relatively large, inflexible and unsightly 50-wire cable running between the outlet and the telephone. Further, the conversion device should allow the replacement of all the old electromechanical telephones being used with new full feature electronic telephones, and also allow the selective replacement of some telephones with electronic telephones while permitting the remainder of the electromechanical telephones to continue in operation. The conversion should be accomplished without modification of the key service unit or the 50-wire cabling or 50-pin outlet connector.
The conversion device should permit full utilization of the many desirable features provided by modern electronic telephones, and not provided by the electromechanical telephones being replaced, such as last number re-dial, automatic re-dial of busy numbers, one touch automatic dialing of stored numbers, memory for storage of telephone, access and credit card numbers, call conferencing, muting for privacy, two-way speakerphone operation, and the many other features provided by electronic telephones. In addition, the conversion device should retain the several benefits of the 1A2 system, and not provided by electronic telephones when used with multiple telephone lines, such as access to all lines without operator assistance, manually operable switches to select telephone lines and place lines on hold, and lights to visually indicate the status of the lines. Preferably, other benefits should be provided by the conversion device not usually provided by either electromechanical or electronic telephones.
In such manner, with use of the needed conversion device, not only will the user be allowed to selectively update existing electromechanical systems easily and at low cost without requiring the services of a telephone technician in order to acquire all the benefits of an electronic telephone, but the resulting telephone system will retain the benefits inherent with multiple-line systems and have benefits not provided by either electronic or electromechanical telephones.